Q: Earlier this year, my cousin and I bought round-trip tickets to fly British Airways from Miami to London.

About a month before our flight, we paid British Airways $168 for two seat reservations. We selected bulkhead seats, near the front of the aircraft, that had extra legroom.

When we boarded the plane, our chosen seats were not in the position presented by the website. A flight attendant politely explained that this problem frequently occurred when a different, bigger plane was used in order to transport more passengers.

I sent an e-mail to British Airways and received a form answer that said it would take some time to resolve my problem "due to the high volume of correspondence." When I came back home, I contacted British Airways several times and left phone messages, but no one ever called back. I disputed the charges on my credit card, but that didn't work. My credit card company denied the dispute because I used the seats even though I knew they were not what I originally purchased.

A: You should have received a bulkhead seat on the plane, as promised. You've uncovered the dark side of an industry practice called "unbundling." That's the act of stripping away all the components of an airline ticket and then selling them back to you — a very profitable but often deceptive airline tactic.

Most airlines continue to behave as if these unbundled items are technically "free" and that there are no guarantees with them. A few years ago, the government ordered domestic airlines to refund baggage fees when they lost luggage. Before, some airlines had refused to do so.

Your credit card company also goofed. Although you received the ticket you paid for, you did not receive the seats you paid for. British Airways draws a distinction, and so should your credit card company. But mostly, British Airways goofed. When it switched its plane — in airline parlance, an "equipment" change — then it was obligated to give you comparable seats. If it couldn't, it needed to refund your reservation fee, no questions asked.

British Airways' initial response to you was acceptable, as long as it followed up with a real answer in a reasonable amount of time. But it didn't. And calling its executives was an exercise in futility. Your best bet was to escalate the case via e-mail.

I contacted British Airways on your behalf. It apologized for giving you the wrong seats and cut you a check for $168.

Christopher Elliott is the ombudsman for National Geographic Traveler magazine. Read more tips on his blog, elliott.org or e-mail him at chris@elliott.org.